Made any changes to that file recently?
To what kind of layout does it open?
Things that can slow the opening of a file:
An external data source reference to a file that uses an invalid IP address. Open Manage | External Datasources to check
A Layout with a very large record set and fields that summarize data from that set.
A script that is performed via script trigger when the file is opened or the initial layout is entered (OnLayoutEnter, OnRecordLoad...) that has a problem.
You may also want to open a recent back up copy of the file and run a recover on it to see if any problems are reported. If all else fails, take the file down off the server, used advanced recovery options to rebuild all indexes in the file, save a compressed copy of this recovered copy and put the compressed copy back on the server.
If you have FileMaker 11 or newer, you can use Advanced Recovery options to rebuild your file's indexes:
- With the file closed, select Recover from the File Menu.
- Select "Use advanced Options"
- Select only: "Copy File Blocks as-is" and "Rebuild Field Indexes Now".